Fuel tank level equalizer system

Abstract

A fuel delivery system for vehicles with more than one fuel tank or a single tank with separate sections under at least some fuel level conditions. The system has an electric fuel pump disposed in the fuel container and a jet pump connected to the electric fuel pump with fuel pickups connected to the jet pump through a siphon. The electric fuel pump powers the jet pump to fill the siphon with liquid fuel and draw fuel through the pickups which are spaced apart in separate sections of the fuel container. When the siphon is completely filled with liquid fuel and the jet pump is operating, any difference in the heads or fuel levels in the sections of the fuel container will cause fuel to flow through the siphon from the section with the greater head to the other section of the tank. This flow, due to the difference in pressure associated with different fuel levels, continues until the fuel levels and, hence, the pressures are substantially the same in each section of the container. Therefore, a single fuel level sensor can be used to monitor the total amount of fuel remaining in the tank or tanks. An air break interrupts the operation of the siphon when the jet pump is not operating to maintain the same fuel level in the sections or tanks even though the vehicle and hence the container or tanks are inclined when the vehicle and pumps are not operating.

We claim: 
     
       1. A fuel delivery system for an internal combustion engine comprising; a fuel pump driven by an electric motor and constructed to be disposed in a liquid fuel container with at least two sections which are separated from each other under at least some fuel level conditions, said fuel pump having a pump inlet disposed adjacent the bottom of the fuel container and a pump outlet for delivering fuel under pressure to the engine, at least two fuel pickups spaced apart and disposed adjacent the bottom of said fuel container each in a separate section and each having an inlet at a lower portion of its associated separate section of the fuel container, an outlet and a valve member which permits liquid fuel to flow through the inlet when the inlet is immersed in liquid fuel and prevents gaseous flow through the inlet in the absence of liquid fuel at the inlet, a siphon communicating and connected with the outlets of all of the pickups, a vacuum producing device having an inlet communicating with the siphon so that when operating the vacuum device removes any gas from the siphon to fill the siphon with liquid fuel and initiate action of the siphon to tend to equalize the level of fuel in all the sections of the fuel container, and an air break disposed above and communicating with the uppermost portion of the siphon to provide air to the siphon when the vacuum device is not operating and the fuel level in the fuel container is below said uppermost portion of the siphon to interrupt the siphon action. 
     
     
       2. The fuel delivery system of claim 1 wherein each of two of the sections of said fuel container comprises a separate fuel tank and at least one pickup is disposed in each separate fuel tank. 
     
     
       3. The fuel delivery system of claim 1 wherein said fuel container is a single fuel tank having the two sections separated from each other at least at certain fuel levels, and at least one pickup is disposed in each separate section of said fuel tank. 
     
     
       4. The fuel delivery system of claim 1 wherein said vacuum producing device comprises a jet pump having a nozzle and a venturi passage constructed to receive fuel discharged from the outlet of said nozzle. 
     
     
       5. The fuel delivery system of claim 1 which comprises an orifice between said inlet of said vacuum producing device and said siphon with an opening large enough to interrupt the siphon when the vacuum producing device is not operating. 
     
     
       6. The fuel delivery system of claim 5 wherein said orifice opening has a size in the range of about 0.020" to 0.040". 
     
     
       7. The fuel delivery system of claim 1 wherein said vacuum producing device comprises a jet pump located generally vertically above said fuel pickups and said jet pump provides sufficient aspiration to prime the siphon to remove any air or fuel vapor from the siphon and deliver liquid fuel to the operating jet pump. 
     
     
       8. The fuel delivery system of claim 1 which also comprises only one fuel level sensor in the fuel container. 
     
     
       9. The fuel delivery system of claim 1 in which said air break has an air inlet which does not admit air to the siphon when the vacuum producing device is operating normally. 
     
     
       10. The fuel delivery system of claim 9 wherein the air inlet is located adjacent the generally vertically highest portion of the siphon. 
     
     
       11. The fuel delivery system of claim 1 wherein the valve member comprises a filter which when immersed in liquid fuel permits liquid fuel to flow therethrough and prevents gaseous flow therethrough when not immersed in liquid fuel. 
     
     
       12. The fuel delivery system of claim 1 wherein the valve member comprises a diaphragm, a valve and a valve seat, the valve is open when the inlet is immersed in liquid fuel to permit liquid fuel to flow through the inlet and the diaphragm closes the valve on the valve seat in the absence of liquid fuel adjacent the inlet to prevent gaseous flow through the inlet. 
     
     
       13. The fuel delivery system of claim 1 which comprises only one fuel level sensor disposed in only one section of the liquid fuel container and responsive to the fuel level in only said one section of the fuel container to thereby monitor the level of all the fuel in the fuel container. 
     
     
       14. The fuel delivery system of claim 1 wherein the vacuum device comprises a jet pump disposed completely within the fuel container and having an inlet communicating with the siphon, a second inlet communicating within the fuel container with the fuel pump outlet and an outlet for discharging fuel received in the second inlet to the fuel container and the flow of fuel from the second inlet to the outlet of the jet pump creates a drop in pressure at the jet pump inlet to remove any gas from the siphon. 
     
     
       15. A fuel delivery system for an internal combustion engine comprising; a fuel pump module constructed to be disposed in a fuel container with at least two sections which are separated from each other under at least some fuel level conditions, a first fuel pump disposed in said module having a fuel inlet disposed adjacent the bottom of the fuel container and a fuel outlet for delivering fuel under pressure to the engine, a jet pump communicating completely within the fuel container with the fuel outlet of the first fuel pump and powered by a portion of outlet fuel from said first pump and having an inlet, at least two fuel pickups spaced apart and each disposed in a separate section of the fuel container adjacent the bottom of its associated separate section of the fuel container and each having an inlet at a lower portion of its associated separate section of the fuel container, an outlet and a valve member which permits liquid fuel to flow through the inlet when the inlet is immersed in liquid fuel and prevents gaseous flow through the inlet in the absence of liquid fuel at the inlet, a siphon communicating and connected with the outlets of all of the pickups and the inlet of the jet pump so that when the jet pump is operating the jet pump removes any gas from the siphon to fill the siphon with liquid fuel and initiate action of the siphon to equalize the level of fuel in all of the sections of the fuel container, and an air break disposed above and communicating with the uppermost portion of the siphon to interrupt the siphon action. 
     
     
       16. The fuel delivery system of claim 15 wherein each section of said fuel container is a separate fuel tank and each said pickup is disposed in a separate fuel tank. 
     
     
       17. The fuel delivery system of claim 15 wherein said fuel container is a single fuel tank having the at least two sections separated from each other at least at certain fuel levels, and at least one pickup is disposed in each separate section of said fuel tank. 
     
     
       18. The fuel delivery system of claim 15 in which the air break has an air inlet which does not admit air to the siphon when the jet pump is operating normally. 
     
     
       19. The fuel delivery system of claim 18 wherein the air inlet is located adjacent the generally vertically highest portion of the siphon. 
     
     
       20. The fuel delivery system of claim 15 wherein the valve member comprises a filter which when immersed in liquid fuel permits liquid fuel to flow therethrough and prevents gaseous flow therethrough when not immersed in liquid fuel. 
     
     
       21. The fuel delivery system of claim 15 wherein the valve member comprises a diaphragm, a valve and a valve seat, the valve is open when the inlet is immersed in liquid fuel to permit liquid fuel to flow through the inlet and the diaphragm closes the valve on the valve seat in the absence of liquid fuel adjacent the inlet to prevent gaseous flow through the inlet. 
     
     
       22. The fuel delivery system of claim 15 which comprises only one fuel level sensor disposed in only one section of the liquid fuel container and responsive to the fuel level in only said one section of the fuel container to thereby monitor the level of all the fuel in the fuel container. 
     
     
       23. A fuel delivery system for an internal combustion engine comprising; a first fuel pump with an electric motor disposed in a fuel container with at least two sections which are separated from each other under at least certain fuel level conditions, said first fuel pump having a fuel inlet disposed adjacent the bottom of the fuel container and a pump outlet for delivering fuel under pressure to the engine, at least two fuel pickups spaced apart and each disposed in a separate section of the fuel container adjacent the bottom of a separate one of the sections of the fuel container, each pickup having an inlet at a lower portion of its associated separate section of the fuel container, an outlet and a valve member which permits liquid fuel to flow through the inlet when the inlet is immersed in liquid fuel and prevents gaseous flow through the inlet in the absence of liquid fuel at the inlet, a siphon connected with the outlets of all of the fuel pickups and having an outlet, a second pump having an inlet communicating with the outlet of the siphon and having a restricted orifice to increase the pressure drop across the inlet of the second pump in response to fluid flow through the orifice for drawing any air and fuel vapor and liquid fuel from the siphon when the second pump is operating, and an air break communicating with the siphon and having an inlet disposed above the siphon which is open for supplying air and fuel vapor from within the container to the siphon when the level of fuel is below the vertically highest portion of the siphon and the second pump is not operating to interrupt the siphon action and closes when the second pump is operating to prevent air and fuel vapor from being supplied to the siphon so that under normal operating conditions the second pump will completely fill the entire siphon and all of the fuel pickups with liquid fuel and while the second pump is operating the siphon will equalize the level of liquid fuel in the sections of the container. 
     
     
       24. The fuel delivery system of claim 23 wherein the air inlet of the air break is disposed generally vertically above the generally vertical extent of the separated sections of the container. 
     
     
       25. The fuel delivery system of claim 24 which also comprises a bypass pressure regulator disposed in the fuel container having a fuel inlet communicating with the fuel outlet of the first fuel pump, a primary fuel outlet constructed to communicate with the engine for supplying liquid fuel to the engine, and a bypass outlet within the fuel container which in normal operation of the first pump bypasses a part of the fuel from the outlet of the first pump, and wherein the second pump is a jet pump disposed completely within the fuel container and having a venturi passage, a fuel inlet associated with the venturi passage which is connected with the outlet of the siphon, and a nozzle connected with the bypass outlet of the pressure regulator for discharging fuel into the venturi passage when the first pump is operating and the regulator bypasses a portion of the fuel from the first pump through the bypass outlet of the regulator. 
     
     
       26. The fuel delivery system of claim 23 wherein the air inlet of the air break is located generally vertically at least substantially as high as the highest portion of the siphon. 
     
     
       27. The fuel delivery system of claim 26 wherein the air inlet of the air break is disposed generally vertically above the generally vertical extent of the separated sections of the container. 
     
     
       28. The fuel delivery system of claim 23 wherein the valve member comprises a filter which when immersed in liquid fuel permits liquid fuel to flow therethrough and prevents gaseous flow therethrough when not immersed in liquid fuel. 
     
     
       29. The fuel delivery system of claim 23 wherein the valve member comprises a diaphragm, a valve and a valve seat, the valve is open when the inlet is immersed in liquid fuel to permit liquid fuel to flow through the inlet and the diaphragm closes the valve on the valve seat in the absence of liquid fuel adjacent the inlet to prevent gaseous flow through the inlet. 
     
     
       30. The fuel delivery system of claim 23 which comprises only one fuel level sensor disposed in only one section of the liquid fuel container and responsive to the fuel level in only said one section of the fuel container to thereby monitor the level of all the fuel in the fuel container. 
     
     
       31. A fuel delivery system for a combustion engine comprising a fuel pump, a liquid fuel container with at least two sections which are separated from each other under at least some liquid fuel level conditions, a fuel inlet disposed adjacent the bottom of the fuel container and connected to the fuel pump, a pump outlet for delivering liquid fuel under pressure to the engine, a vacuum producing device having an inlet, at least two fuel pickups spaced apart and each disposed in a separate section of the fuel container and adjacent the bottom of its associated separate section of the liquid fuel container and each having an inlet for liquid fuel at a lower portion of its associated separate one section of the liquid fuel container, and a siphon communicating with all the fuel pickups and the inlet of the vacuum producing device so that when operating the vacuum device removes any gas from the siphon to fill the siphon with liquid fuel and initiate action of the siphon to substantially equalize the level of fuel in all the sections of the fuel container and an air break disposed above the uppermost portion of the siphon and communicating with the vacuum device so that when the vacuum device is not operating, air enters the inlet of the vacuum device to interrupt the siphon action to prevent any transfer of fuel through the siphon between the separate sections of the fuel container. 
     
     
       32. The fuel delivery system of claim 31 which comprises only one fuel level sensor disposed in only one section of the liquid fuel container and responsive to the fuel level in only said one section of the fuel container to thereby monitor the level of all the fuel in the fuel container.